Russian Journal of Applied Chemistry, 2012, Vol. 85, No. 7, pp. 995−1002.
Pleiades Publishing, Ltd., 2012.
Original Russian Text © A.B. Venediktov, S.V. Korenev, D.B. Vasil’chenko, A.V. Zadesenets, E.Yu. Filatov, S.N. Mamonov, L.V. Ivanova,
N.G. Prudnikova, E.Yu. Semitut, 2012, published in Zhurnal Prikladnoi Khimii, 2012, Vol. 85, No. 7, pp. 1025−1032.
AND INDUSTRIAL INORGANIC CHEMISTRY
On Preparation of Platinum(IV) Nitrate Solutions
A. B. Venediktov, S. V. Korenev, D. B. Vasil’chenko, A. V. Zadesenets, E. Yu. Filatov,
S. N. Mamonov, L. V. Ivanova, N. G. Prudnikova, and E. Yu. Semitut
Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Krastsvetmet Open Joint-Stock Company, Krasnoyarsk, Russia
Received February 28, 2011
Abstract—The parameters of the processes underlying the current technology of preparation of a Pt(NO
solution were studied and optimized. The basic problems of the process scheme were determined, including limited
storage time of solid hexahydroxoplatinum (IV) acid. Approaches were suggested for increasing the yield and the
storage time of intermediate products and for simplifying the conditioning scheme of platinum (IV) nitrate with
a signiﬁ cant reduction of time and energy costs.
To date, platinum (IV) nitrate (PN) may be considered
as the most promising precursor for the preparation of
supported platinum catalysts, used for post-combustion
of exhaust gases, in particular. This is primarily due to
the fact that a conditioned nitric acid solution of PN is
virtually free from catalyst poisons, especially alkali
metal and Cl
ions, and is therefore superior to precursors
with another ligand environment of platinum (IV). In
addition, PN has a low thermal stability.
Studies of the acid solutions of NP by the
method showed that the solution composition substantial-
ly changes with time. The same conclusion was made in
. The chemistry of these processes remains unknown.
Practically no data are available in the literature on the
forms of platinum in solutions with a high concentration
of metal (c
~ 2 M) and nitric acid (up to ~ 10 M),
including existence, nuclearity, and time transformations
of forms, and features of the transformation processes.
Only two studies [1, 2] are published that have a catalytic
orientation and are devoted to commercial PN solutions at
deep alkalization ([OH-]: [Pt] ~ 10). Despite a number of
discrepancies, the above studies conﬁ rmed polynuclearity
of the Pt (IV) forms and presence of bridging hydroxo-and
(or) oxo groups between mononuclear fragments. Though
the above studies have used the most up-to-date methods
(EXAFS, TEM, NMR), their conclusions are too general
and contain no experimental data on the speciﬁ c platinum
forms in the solutions.
Available in Russia technology of the preparation of
PN solutions is to a certain extent similar to that proposed
in a patent , but is much simpler and improved. The
essence of both methods is expressed by the scheme:
where М is K
 or Na
(in a current process), with the
concentrations in the ﬁ nal product must be
strictly controlled in the latter process.
The principal problem in terms of technology is small
storage time of solid H
prior to preparing PN
solutions: 2 or no more than 3 months at best. After expir-
ing these periods, the properties of the reagent change. As
a result, the resulting ﬁ nal product, a nitric acid solution
of PN, does not pass control tests.